Later on there is 5 vampires called the originals, they want to kill Elena because of her doppelganger, which is an identical person to you that isn't your twin. Damon and Stephan, the two brothers that love Elena protect her. They don't let anything happen to her and they always put her before anyone else. Elena protects her brother and friends, although the Vampires are powerful, witches are even more powerful. Her best friend is a witch, but not just a regular witch shes a special witch.
Elena's brother doesn't like Damon or Stephan, but both of the brothers protect him because Elena asked them to. Most vampires can't be in the sunlight but Damon and Stephan have special daylight rings, so they can be wherever they want. Everyone thinks Damon is a bad person because he will do whatever it takes to make sure Elena stays safe, however Stephan is more cautious and everyone in the show likes him because he's a better person.